The default/fallback/substitution fonts are those used when an application or webpage doesn't specify a specific font or when a character glyph is not available in the selected font. When the CSS contains "font-family: sans", which font is that?
Note: I'm using an Ubuntu-based distribution, but the details should apply anywhere fontconfig is used.

I enjoy using the interactive Python console as a calculator, but typing python3 and then from math import * was annoying. So I scripted it into a simple command I've named cpy. Maybe someone else can use it.

I just updated the design on this website (finally!) and needed to make image sprites for the github/twitter/linkedin icons. I know there's ways to create image sprite sets NodeJS and Gulp/Grunt, but what's the fun in that!?

The Jinja templating engine works well to create LaTeX templates for generating PDF files. The only issue is the default Jinja block, variable, and comment identification strings can conflict with the LaTeX commands. A solution is to change the Jinja environment to mimic the LaTeX environment.